My boyfriend and I adopted 2 guinea pigs, Trudy and Peppa, in October. Both are females and are about 8 months old. We recently saw a hairless piggy for adoption in our town and after passing her so many times we decided we had to take her home On Saturday (2 days ago).

We did basically everything wrong in the introduction process and I think we made it more difficult. We introduced them in "neutral territory" and it went well, but we put them in the cage right after which I realize now was a mistake. They seemed ok for a day but then Trudy began attacking the new piggie. During the day yesterday we kept them in two cages that were touching so they could see each other. We let them be in the same cage for a bit during the day and supervised and all seemed ok. Then, last night we left them alone for a bit in the cage (I know I know, we shouldn't have) and came back and the new piggie had scratches all over her. Nothing too alarming but I could tell they had been fighting and one scratch was a bit red. They did seem to be mostly scratches and not bites. Nonetheless, Trudy now can't be near her too long without fighting.

What to do now? I feel like we messed up the introduction and I'm wondering how we can best fix it. The new baby is hairless and very small so I don't want her to get hurt. At the same time, it has only been three days and I haven't lost hope that they can get along. BTW, the cage is 2 feet by 4 feet and has a divider in the middle with a ramp.

You're supposed to put them in the cage after the neutral area. But the cage has to be large enough, and it has to have been thoroughly cleaned so that nothing about it, on in it, smells like any of the pigs.

I was worried the cage was too small. Luckily, we have a second 2 x 4 cage in storage that can connect so I'm thinking we will connect them to have one 4 x 8 cage instead.

I have read a bunch of stuff about introductions the past day, hence my comment that we did everything wrong. I should have done more research beforehand. I'm wondering if there's a way to start over. As we speak, I have them out in "neutral territory," and so far all has been well, a little rumbling once or twice but no fighting and the two older pigs have been popcorning and seem happy. Baby pig is still a bit nervous.

After this, I imagine we should try to keep them in separate cages for now?

Well, you shouldn't put them together at all until you're ready to put them in a big cage and leave them there. Guinea pigs are wired to establish dominance over other pigs they meet, and every time you put them together, you force them to start the process all over again. It's stressful, and should be avoided.

But two 2x4 cages aren't really suitable unless you can totally open them up into a 4x4 with no walls. There's not enough room for them to run, and they'll have to get through some narrow area to get to the other side, and that's a good place to get trapped.

As you have noticed, hairless guinea pigs are very vulnerable to injury (they lack the hair that would provide some protection). Have you done research on keeping a hairless guinea pig? Is the room warm enough? Ditto everything bpatters has to say.

You also should have quarantined the new pig for 3 weeks before putting them together. Lets hope it doesn't have an upper respiratory infection or something like that, because now all your pigs will have it.

If you've put them together in a neutral territory and they are getting along, you should keep them together. But you should have had the bigger cage all ready to go, cleaned and rearranged so it's like a new cage for all the pigs. Constantly putting them together and then separating them is incredibly stressful and may make it impossible for them to eventually get along.

A skinny pig is considered a special needs pig and needs special care. You need to have the room warm enough to keep the pig comfortable and there should be snuggle sacks in the cage to provide extra warmth and comfort. Fleece and towel bedding is a must. They also eat much more than an average pig and have a larger output too (a good quality diet is vital). So you will be cleaning the cage much more often.